(-)-Methyl jasmonate

METHYL JASMONATE is a volatile component of jasmine flower absolute. It is a colorless to pale yellow liquid, bp0.125 kPa 116–118 °C, d20 20 1.022–1.028, n20 D 1.473–1.477, possessing an odor reminiscent of the floral heart of jasmine. Synthesis of the title compound is accomplished by reaction of (2Z)-2-buten-1-yl bromide with Li in the presence of copper-(I) iodide, and the product is treated with a mixture of 2-methylene- and 4-methylene-3-oxocyclopentylacetic acid methyl ester. The aforementioned ester mixture is obtained by reaction of methyl 3-oxocyclopentylacetate with formaldehyde. An alternative route uses a palladium-catalyzed decarboxylation of the readily available substituted allyl 2-oxocyclopentanecarboxylates, which leads to the corresponding cyclopentenones. Addition of dimethylmalonate, with subsequent saponification/decarboxylation and, if necessary, (Z)-selective hydrogenation, yields methyl jasmonate: Methyl jasmonate exists in an equilibrium mixture in which the trans-isomer dominates. But of all possible four enantiomeric isomers, chiefly the minor (+)-cis-isomer is responsible for the typical sensory properties of methyl jasmonate. Therefore, several approaches to obtain this material selectively have been developed either by directed syntheses or by enrichment using special isomerization distillation techniques. Methyl jasmonate is used in fine fragrances where it provides rich, soft effects in jasmine and muguet compositions.

개요Methyl jasmonate has a powerful, floral-herbaceous, sweet, persistent odor. Can be isolated from jasmine oil; or it may be prepared synthetically (probably in the trans-form) from muconic acid via the methyl-3-oxo-cyclopenthyl acetate.

출처Reportedly identified in jasmine oil (Jasminum grandiflorum L.) and in Tunisian rosemary. Also found in lemon peel oil, peppermint oil and green and fermented tea

용도Methyl ester in perfumes.